1. Field of the Invention
This invention relates generally to the field of farm tractors having accessories driven by power supplied by the tractor and, more particularly, to an all-electric tractor having an A.C. power source which provides power both for energizing induction motors for driving the tractor's wheels and also for energizing electric accessories associated with the tractor.
2. Description of the Prior Art
The wheels or other traction means of farm tractors or other land vehicles have traditionally been driven by internal combustion engines through mechanical coupling means, including complex transmissions. Furthermore, accessories were mechanically driven by a power-take-off (PTO) driven by the engine. It is also broadly known to drive the wheels of a land vehicle by A.C. induction motors controlled by cycloconverters. In addition, there has recently been developed a log stacker whose wheels are driven by D.C. motors and whose log handling mechanism is driven by A.C. motors. Also, there has been disclosed the concept of driving the wheels of both a truck and its trailer by individual wheel motors powered by a generator located in the truck.
Examples of such prior art systems are found in the following U.S. patents and publications:
______________________________________ Patents U.S. Pat. Nos. ______________________________________ 3,577,050 Ringland et al May 4, 1971 3,584,276 Ringland et al June 8, 1971 3,690,395 Spiller et al Sept. 12, 1972 3,713,504 Shimer et al Jan. 30, 1973 3,860,081 Moll et al Jan. 14, 1975 ______________________________________